Hybrid battery load test and intelligent tester have different results

You would only get good results, when you load test the modules using an automotive headlamp bulb, when you have the pack on your work table.

You can also discharge/charge the pack while in the car, and observe what voltage readings you get on tech stream.

The voltage sense wires are a big culprit in this case, since you got NP discrepancies on the modules you tested. Clean the corrosion, and test again.

PS: Without doing a load test, you'd never get the bad modules.

 

You need to do capacity test instead of load tests. Discharging a module for 1 to 2 minutes does not drop the voltage enough to find the weak ones. Capacity testing will. Weak modules discharge to 6V from fully charged in 15 minutes. Strong modules discharge to 6V from fully charged in 30 minutes. That is with using a 12V 55w headlight lamp with both filaments connected. Try that.

 

No.

 

This is not the typical experience of most who have opened the HV pack and inspected it. Most of the copper plates and fasteners linking the modules to create the 200+ volt battery have corrosion on them after several years of use due to condensed moisture inside the battery pack which is inevitable except in arid regions. Localized corrosion such as yours could mean that the first module is venting gas ever so slightly. The modules are vented to reduce the possibility that they will explode.

 

While corrosion is much more prevalent with the anode than the cathode, cathodic corrosion does occur in some circumstances. Personally, I don't know what conditions promote it.

 

It won't damage the modules. That would be like 1.0V per cell. Going beyond that, would be damaging to them.

 

I seems not to get what these values mean. Y are they in the 0.3....? Aren't they supposed to be in their 7...or 8..?

 

Yes. The inner pack modules run hotter over their lifetime and numerous failures are reported there but there are exceptions so it's not a hard and fast rule. During my (wack-a-mole) repairs, I reshuffled the whole pack to move the middle modules to the ends.

 

It is the delta voltage –> starting voltage - ending voltage

 

Alright, thanks a lot.

 

Please explain what is the Value used as "fully charged" condition in this test.
Thanks

 

Thanks for your info, you must know those battery module very well, It is cheap way testing capacity of battery, I fully charge 3 module using 24V smart car charger with timer, Then I did 12V 55W car light test, Good modules last for 30+min discharge to 6V, while weak battery last less than 15 min.
It is also a cheap way to recondition batteries as well, I used this cheap methods to charge and discharge battery to recondition batteries, After 2 times. all batteries can keep car light bulks for more than 40 to 50 min. I used 3 car light bulbs with 24V smart car battery charger, I recondition 28 modules in less than 1 day.

 

This looks a risky way to charge, although discharge to 6V (if you catch the cutoff correctly) seems pretty good. The problem with charging with a charger not made for NIMH is that you have to turn down the charging current as you get above 8.4 or so volts. If you don't, the modules will expand and more importantly will outgas -- and you'll never get that electrolyte back in there, so you don't want a lot of outgassing for module long life. I wrote up a Wiki on my experiences repairing the HV pack and its modules including the charge cycling and the rebalance, if anyone is interested to go through the process.

 

Alot of interest. Drop the link here